select *from dept left join emp on dept_id = dept.id union select *from dept right join emp on dept_id = dept.id; 合并但不去除重复 select *from dept left join emp on dept_id = dept.id union all select *from dept right join emp on dept_id = dept.id; 注意:union语句 必须使用在...
若要输出 DataFrame 中的所有列,请使用columns,例如df_customer.columns。 选择列 可以使用select和col选择特定列。col函数位于pyspark.sql.functions子模块中。 Python frompyspark.sql.functionsimportcol df_customer.select( col("c_custkey"), col("c_acctbal") ) ...
(7)类别列 独热编码OneHotEncoder from __future__ import print_function from pyspark.sql import SparkSession from pyspark.ml.feature import OneHotEncoder,StringIndexer spark=SparkSession.builder.appName('OneHotEncoderExample').getOrCreate() df=spark.createDataFrame([(0,'a'),(1,'b'),(2,'a'...
return input_df.select([col(col_name).cast("int") for col_name in input_df.columns]) def sort_columns_asc(input_df): return input_df.select(*sorted(input_df.columns)) df.transform(cast_all_to_int).transform(sort_columns_asc).show() def add_n(input_df, n): return input_df.sele...
You can see that age_square has been successfully added to the data frame. You can change the order of the variables with select. Below, you bring age_square right after age. COLUMNS = ['age', 'age_square', 'workclass', 'fnlwgt', 'education', 'education_num', 'marital', ...
The numeric input columns (temp, atemp, hum, and windspeed) are normalized, categorial values (season, yr, mnth, hr, holiday, weekday, workingday, weathersit) are converted to indices, and all of the columns except for the date (dteday) are numeric. The goal is to predict the count...
(self,df):forcol_indf.columns:try:ifself.mode[col_]=='default':df=self.missing_value_fill_default(df,col_)ifself.mode[col_]=='mean':df=self.missing_value_fill_mean(df,col_)ifself.mode[col_]=='customize':df=self.missing_value_fill_customize(df,col_,self.value)except:continue...
subset– Use this to select the columns for NULL values. Default is ‘None. Alternatively, you can also useDataFrame.dropna()function to drop rows with null values. PySpark Drop Rows with NULL Values DataFrame/Dataset has a variablenawhich is an instance of classDataFrameNaFunctionshence, you ...
when ((d1.{rf} is not null) and (tab2_cat_values==array()) and ((cast(d1.{rl}[0] ...
>>>frompyspark.sql.typesimportIntegerType>>> SparkSession.udf.register("stringLengthInt",lambdax: len(x), IntegerType())>>> SparkSession.sql("SELECT stringLengthInt('test')").collect() [Row(stringLengthInt(test)=4)] SparkSession.catalog.listDatabases: ...